Regulating apparatus



All

Patented June 21, 1938 UNITED STATES PATENT OFFICE REGULATING APPARATUS Joseph F. Kovalsky, Turtle Creek, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation oi Pennsylvania Application January 30, 1937, Serial No. 123,239

11 Claims.

a primary control relay is employed having a contact member that is moved in accordance with Variations in a regulated quantity and which enages a' cooperating contact member to close a circuit through which a correction in the regulated quantity is effected, it is also necessary to move the secondary contact member to prevent the regulator from hunting. The cooperating contact member when actuated to prevent overshooting of the corrective action is moved to interrupt the control circuit sooner than it otherwise would. .It is desirable that said secondnamed or cooperating contact member be normally held in a definite position from which it is moved after engagement by the first-named contact member, and to which position it is gradually returned to efiect a reclosing of the control circuit unless the first contact member, which is responsive to the regulated quantity, has been moved to such position that no circuit is completed upon the return of the second member to its normally fixed position. It is desirable that the movement of said second-named contact member in a direction to efiect a reclosing of the interrupted circuit be slow, so that the reclosing of the circuit will be a function of the time following its interruption and be also dependent upon the position of the contact member that moves in accordance with the regulated quantity. The slow movement of the cooperating contact member to its normally fixed position may be effected by damping means such as a dashpot, but liquid filled dashpots possess limitations dependent upon the viscosity of the fluid employed, the temperature and the presence of foreign matter,

such as dirt.

It is an object of my invention to provide a regulating system of the above indicated character in which anti-hunting means is provided for varying the duration of the corrective action to vide a regulator of the above-indicated character in which the anti-hunting means is controlled electromagnetically.

My invention will be better understood by reference to the accompanying drawing, in which Fig. 1 is a diagrammatic viewof circuits and apparatus illustrating one preferred embodiment of the invention;

Fig. 2 is a view illustrating curves disclosing certain characteristics of the invention; and

Fig. 3 is a diagrammatic view of a portion of.

the circuit showing a modified form thereof.

Referring to Fig. l, a generator I is employed having an armature winding 2 connected to circuit conductors 3 and 4 and a field winding 5 that may be energized from any suitable source of direct current, such as an exciter generator 6, as controlled by a rheostat I operatively connected to .a pilot motor 8. The pilot motor is provided with an armature winding 9 and field windings i2 and I3 through which circuits may be closed by contactors l4 and I5, respectively, to supply energy to the motor 8 from a battery l6 for operating it in the one or the other direction in accordance with the operation of a relay i'l that is controlled by the voltage between conductors 3 and 4. The primary relay ll comprises a magnetic core structure I! having a control winding l8 on a winding leg thereof that is connected by conductors 2i and 22 to be energized in accordance with the voltage between load circuit conductors 3 and 4. The ends of the core [9 are spaced apart to provide room for a movable armature 23 positioned partly between them to provide a double air gap. The armature is carried by a lever 24 mounted upon a pivot 25 and biased by a spring 26 against the pull of the armature 23. A pair of contact members 21 and 28 are carried at the lower end of the relay arm or lever 24 and are adapted to engage contact members 3| and 32, respectively, mounted on levers 33 and 34 which are mounted, respectively, on the fixed pivots 35 and 36. The levers 33 and 34 are mechanically connected together by a link 31 in such manner that the upper or contact carrying ends thereof move in opposite directions as viewed in the figure. A spring 38 is provided for normally biasing the levers 33 and 34 into engagement with stops 4| and 42 respectively, to establish normally fixed positions for the contact members 3| and 32. A magnet 43 is provided having a winding '44 for biasing the levers 33 and 34 against the pull of the spring 38. One side of the winding 44 is connected by conductor 45 to one terminal of a source of direct current energy 46 and the other side is connected by conductor 41 through a damping circuit comprising a resistor 48 and a condenser 49 to the opposite terminal of the source 48.

I1 the system is in operation and the voltage oi the generator I is as at its. desired value, the energization of the primary relay winding 18 is suflicient to balance the pull of the adjusted spring 28 so that the contact members 21 and 28 will be positioned between the contactmembers 3| and 32 out of engagement therewith, as illustrated. If the voltage of the generator increases above its desired value, the energization of the winding I8 increases, thus increasing the pull on the armature 23 causing the lever 24 to move toward the right to cause engagement of the contact 28 with the normally fixed contact 32. A circuit is thus completed from the positive terminal oi the battery 46 through conductor 5|, the winding 52 of the relay i4 through conductor 53, contact members 32 and 28, the winding 44 and conductor 45 to the negative terminal of the battery 45, energizing the relay I 4 and causing the contact members 54 and 55 thereof to be moved to their circuit closing positions. The contact members 54 complete a circuit from the battery l8 through the field winding I2 and armature winding 9 oi the motor 8 to operate the rheostat I in a direction to decrease the excitation of the generator field winding 5 to decrease the generator voltage. The contact members 55 complete a circuit from the positive terminal of the battery 48 through conductor 5|, contact members 55, conductor 41, winding 44, and conductor 45, thus energizing the magnet 43 and causing the lever 34 to be moved in a clockwise direction about the pivot 38 to move the contact member 32 toward the right. If the initial movement of the primary relay contact member 28 is just enough to cause engagement of the contact members 28 and 32, this movement oi. the contact member 32 interrupts the above traced circult through the winding 52 of the secondary relay l4 causing the relay to drop to its circuit, interrupting position after a predetermined short time interval determined by the condenser 58,

.which condenser provides a source of current through the winding 52 for a sufficient time to insure that the rheostat arm 51 will move a dis movement of the relay contact member 32 towardthe right takes place abruptly upon the closure of the circuit through the winding 44, and, after the time interval necessary to cause the relay l4 to interrupt the circuit through the contact members 55, introduces the damping circuit consisting of the condenser 49 and the resistor 48 into the circuit of the winding 44. A charging current flows through this circuit from the battery 45 to charge the condenser 49, the duration of which is determined by the values assigned to the particular condenser and resistor 49 and 48, respectively. This charging current maintains a partial energization of the magnet 43, permitting a gradual decrease only in the current through the winding 44 to permit a gradual movement of the lever 34 in a counterclockwise direction against the stop 42 to bring the contact member 32 to its original or normally stationary position.

Referring to Fig. 2, the curve 8i illustrates a condition under which the movement of the contact member 32 to its normally fixed position takes place gradually, the distance through which it moves being proportional to the timeafter the interruption of the circuit through the contact member 32 and which curve illustrates the characteristic most generally desired. The damper circuit may be so designed by varying the resistance of the resistor 48 and the capacitance of the condenser 49 that.curves lying generally between the curves 82 and 63, shown in Fig. 2, may be produced. The condition represented by curve 82 is one in which no movement of the contact member 32 toward its fixed position takes place for a predetermined time after the circuit through the contact member 52 has been interrupted, after which predetermined time a relatively rapid movement with respect to time takes place during the relatively level portion of the curve 62, the rate of movement decreasing as indicated by the right-hand portion of the curve which turns upwardly. The condition represented by the curve 82 is one in which a very rapid movement of the contact member 32 toward its normally fixed position takes place immediately after interruption of the circuit through the contact member 32, the amount of movement per unit of time decreasing as shown by the right-hand portion of the curve which turns steeply upwardly.

If the amount of increase in the voltage of the generator I above its desired value is suillcient to cause a considerable initial movement of the lever 24 toward the right, the contact member 28 may remain in engagement with the contact member 32 when it is moved toward the right by the magnet 43, in which case the motor 8 will continue to move until the decrease in the generator voltage has become sufiicient that the contact 28 of the primary relay l'l moves out of engagement with the contact member 32. In this case, the amount of correction in generator voltage necessary to efiect separation of the contact members 28 and 32 will not move the contact member 28 sufiiciently to the left for it to remain out of engagement with contact member 32 after the contact member 32 has moved back to its normally fixed position. A time interval of relatively short duration will occur after separation of the contact members 28 and 32, before the gradual movement of the contact member 32 toward the left, as above described, will cause a reengagement between contact members 28 and 32 to again effect operation of the contactor l4 and of the motor 8 to further decrease the excitation of the generator I. Upon reengagement of the contact members 28 and 32, the anti-hunting magnet 43 will be reenergized and move the contact member 32 abruptly toward the right, as above described, permitting it to again return to its illustrated position.

If the departure ofthe regulated voltage from ;its desired value is sufficient that the bias of the relay Ii maintains the contact member 28 in engagement with the contact member 32 when actuated to the right by the magnet 43, the contact members '32 may be brought into engagement with the contact member 28 several times before the contact member 28 is moved sufiiciently toward the left that it will'not be re- ;engaged by the contact member 32 when the contact member 32 is moved to its fixed or illustrated position upon deenergization of the winding 44. The duration of each successive time interval in which the contact members 28 and 32 are out of engagementduring' such series of regulator operations will increase as the regulated quantity approaches its desired value, since, as the contact member 28 moves to its central position, the time required for the contact memher 32 to move from its extreme right-hand posi- 75 of the battery 46 through conductor 64, the winding 65 of the secondary relay l5, conductor 66, relay contact members 3| and 21 and conductor 45 to the negativeterminal of the battery 46 to operate the secondary relay I5 to its circuit closing position. Upon operation of the relay I5 to its circuit closing position, the contact members 61 close a circuit from the battery It through the motor field winding l3 and armature winding 3 to operate the motor 8 in a direction to increase the excitation of the generator field winding 5, and the relay contact members 68 close a circuit in shunt relation to the damping circuit between the junction points 63 and II in a manner similar to the contact member 55, as explained above, thus energizing winding 44 of the anti-hunting magnet 43, in the same manner as explained above upon closure of the contact members 55 of the relay I4. The link 31 between levers 33 and 34 causes the contact member 3| to be moved toward the left. or away from the contact member 21 at the same time that the lever 34 is moved in a clockwise direction to move the contact member 32 toward the right, thus interrupting the circuit through the contact members 21 and 3| in the same manner as pre- I viously explained for the circuit through the contact members 28 and 32. If the decrease in the regulated voltage below its desired value has vents immediate interruption of the circuit there-' through, the voltage correction will occur in a series of steps upon repeated reengagement -be tween the contact members 21 and 3|, the duration of the successive current interruptions by these contact members increasing as the regulated quantity approaches its desired value in the same manner as explained above for the circuit through the contact members 28 and 32. It will thus be seen that upon a relatively large variation in the regulated quantity from its desired value, the rate of correction in the regulated quantity is rapid in its initial stage and decreases to a step by step correction, the time intervals increasing between the steps as the regulated quantity approaches its desired value, thus giving time for a correction effected by operation of the motor 8 to be felt at the terminals of the generator '2, so that a quick corrective action is initiated and an accurate correction is effected.

Referring to Fig. 3, a circuit is employed-4n which a copper oxide rectifier 12 is substituted for the resistor", the rectifier 12 being so connected that a high resistivity to the flow of current in the direction of the arrows is ofiered while a low resistivity to flow of current in the 1 separated, if the desired time interval for completely charging the condenser 43 is to be available aiter an interruption of the circuit through the contact members 55 or 68 to provide the desired rate of decrease in energization of the anti-hunting winding 44. In certain installations, this is difficult to achieve with the resistor 48 in series with the condenser 43 and a rectiiier 12 may be then substituted for the resistor which, because of its low resistance characteristic in one direction permits an immediate discharge of the condenser 49 upon closure of a circuit through either the contact member 55 or the contact member 68 while requiring an appreciable time element for the charging of the condenser 49 through the winding 44 upon the opening of the above indicated circuit.

Many modifications in the apparatus and circuits illustrated and described may be made within the spirit of my invention and I do not wish to be limited otherwise than by the scope of the appended claims.

I claim as my invention:

1. In a regulating system, in combination, a control relay having contact means positionally responsive to a quantity to be regulated and contact means cooperatively related thereto, means responsive -to the engagement of said cooperatdamping means for, permitting a gradual return only of said second named contact means to its initial position.

2. In a regulating system, in combination, a

control relay having contact means positionally responsive to a quantity to be regulated and contact means cooperatively related thereto and normally biased to a given position, means responsive to the engagement of said cooperating contact means for controlling said regulated quantity, anti-hunting means comprising electroresponsive means energized upon engagement of said contact means for abruptly movingsaid second named contact means in a direction away from said first named contact means, and means for permitting a gradual deenergization only of said electroresponsive means to permit a gradual return of said second named contact means to its initial position.

3.'In a regulating system, in combination, a control relay having contact means positionally responsive to a quantity to be regulated and cooperating contact members normally biased to a given position, means actuated upon engagement of said contact members for controlling said regulated quantity, electroresponsive means energized upon engagement of said contact members for abruptly moving said second named bers for controlling the regulated quantity, means actuated upon engagement 0! said cooperating contact members for abruptly moving said second named contact members in a direction away from said first named contact members, and electromagnetic damping means for permitting a radual returnonly of said second named con tact members to said given positions after separation of said cooperating contact members.

5. In a regulating system, in combination, a control relay having contact means positionally responsive to a quantity to be regulated and contact means normally biased to a given position and cooperatively related to the first named contact means, means comprising a secondary relay actuated upon engagement of said cooperating contact means for controlling said regulated quantity, electroresponsive means energized upon operation 01' said secondary relay to its circuit closing position for abruptly moving said second named contact means in a direction away from said first named contact means, a

damper circuit comprising a condenser and re-.

sistor in series circuit relation for permitting a gradual deenergization only of, said electroresponsive means upon operation 01' said secondary relay to its deenergized position.

6. In a regulating system, in combination, a primary relay having contact means positionally responsive to a quantity to be regulated and contact means cooperatively related thereto and normally biased to a given position, motor operated means for controllingsaid regulated quantity,

secondary control relay means responsive to the engagement of said primary relay cooperating contact means for controlling said motor operated means, electromagnetic means energized upon operation of said primary relay to a circuit closing position for abruptly moving said second named contact means in a direction away from said first named contact means, and a damper circuit for permitting a gradual deenergization only 01' said electroresponsive means after separation of said contact members to permit a gradual return of said second named contact means to said given position.

'I. In a regulating system, in combination, a primary relay having contact means positionally responsive to a quantity to be regulated and contact means cooperatively related thereto and normally biased to a given position, motor operated means for controlling said regulated quantity, secondary control relay means responsive to the engagement of said primary relay cooperating contact means for controlling said motor operated means, and electromagnetic means energized upon operation or said primary relay to a circuit closing position for abruptly moving said second, named contact means in a directionaway from said first named contact means, and a damper circuit for permitting a gradual deenergization only of said electroresponsive means after separation of said contact members to permit a gradual return of said second named contact means to said given position, said resistor having a high resistance characteristic with respect to current flowing to charge said condenser and a low resistance characteristic with respect to current flowing to discharge said condenser.

8. In a regulating system, in combination, a primary relay having contact means positionally responsive to a quantity to be regulated and contact means cooperatively related thereto and normally biased to a given position, motor operated means for controlling said regulated quantity, secondary control relay means responsive to the engagement of said primary relay cooperating contact means for controlling said motor operated means, electromagnetic means energized upon operation of said primary relay to a circuit closing position for abruptly moving said second named contact means in a direction away from said first named contact means, and an energy storing damper circuit comprising a resistor and condenser connected in series for permitting a gradual deenergization only of said electromagnetic means, said resistor having a high resistance characteristic with respect to current flowing to charge said condenser and a low resistance characteristic with respect to current flowing to discharge said condenser.

9. In a regulator system, in combination, a primary control relay having contact members movable in accordance with variations in the regulated quantity and contact members cooperatively related to said first named contact members and normally biased to predetermined stationary positions, means controlled by engagement of said cooperating contact members for efiecting a correction in the regulated quantity, and electroresponsive anti-hunting means actuated upon the initiation of a. corrective action for moving said normally stationary contact members in a-direction away from the first named contact members, said anti-hunting means including an energy storing circuit for permitting a gradual return only of said normally stationary contact members to their initial position.

10. In a regulator system, in combination, a primary control relay having contact members movable in accordance with variations in the regulated quantity and normally stationary cooperating contact members, means controlled by engagement of said contact members for efiecting a correction in the regulated quantity, and electroresponsive anti-hunting means actuated upon the initiation of a corrective action for moving said normally stationary contact members in a direction away from the first named contact members, said anti-hunting means including an energy storing circuit including a condenser and resistor connected in series for permitting a gradual return only of said normally stationary contact members to their initial position.

11. In a regulator system, in combination, a primary control relay having contact members movable in accordance with. variations in the regulated quantity and normally stationary cooperating contact members, means controlled by engagement of said contact members for effecting a correction in the regulated quantity, and electroresponsive anti-hunting means actuated upon the initiation of a corrective action for moving said normally stationary contact members in a direction away from the first named contact members, said anti-hunting means including an energy storing circuit including a condenser and resistor connected in series for permitting a gradual return only of said normally stationary contact members to their initial position, said resistor having a higher resistivity to the flow of charging current to said ,condenser than to the how of discharging current from said condenser.

JOSEPH F. KOVALSKY. 

